Using Omaha OneClick plugin

If Omaha is already installed on user's machine, Omaha OneClick plugin allows users to install new applications without downloading tagged metainstallers. In short, the plugin launches Omaha, which is already installed, and passes the tag (the one which tagged metainstaller contains) within command line arguments. In this case, when user clicks link/button on the webpage, the actual installation process will be started instead of metainstaller downloading process.

To be able to use Omaha OneClick plugin on your server's webpage, the following changes are required:

• Update kSiteLockPatternStrings constant array in base\constants.h file to contain pattern matches your webpage (where OneClick plugin is working) domain
  • Developers can use one additional pattern. It can be defined in OneClickHostPattern variable under HKEY_LOCAL_MACHINE\Software\{OmahaCompanyName}\UpdateDev registry path.
• (optional) Change kPluginDomain constant in base\const_addresses.h file to identify your company. Using your company domain is the common practice.
• Make sure all the constants inside the omaha JavaScript object (see below) have the same values as defined in respective Omaha source files

Below is the sample code which illustrates how Omaha OneClick plugin can be used via JavaScript:

var appguid = "{AAAAAAAA-BBBB-CCCC-DDDD-EEEEEEEEEEEE}";
var appname = "Application";
var needsadmin = "prefers";
var extraParameters = "&lang=en&usagestats=1";

// create omaha object with necessary constants
// make sure all the constants have the same values
// as defined in respective Omaha source files
var omaha = {};
omaha.oneClickVersion = 9;         // defined in VERSION file
omaha.domainName = "google";       // defined in main.scons
omaha.oneClickMimeType =           // defined in base\const_config.h
  "application/x-vnd." + omaha.domainName +
  ".oneclickctrl." + omaha.oneClickVersion;
omaha.companyName = "Google";      // defined in main.scons
omaha.oneClickProgId =             // defined in plugins\update\config.cc
  omaha.companyName + ".OneClickCtrl." + omaha.oneClickVersion;

// set up OneClick

function createOneClickObject() {
  var obj = document.createElement("object");
  obj.type = omaha.oneClickMimeType;
  obj.id = "OneClickCtrl";
  obj.style.position = "absolute";
  obj.style.top = "-5000px";
  obj.style.left = "-5000px";
  document.body.appendChild(obj);
  return obj;
}

try {
  new ActiveXObject(omaha.oneClickProgId);
  omaha.oneclickPlugin_ = createOneClickObject();
} catch (e) {
  var mimeType = navigator.mimeTypes[omaha.oneClickMimeType];
  if (mimeType && mimeType.enabledPlugin) {
    omaha.oneclickPlugin_ = createOneClickObject();
  }
}

omaha.oneclickPlugin_ && (omaha.oneclick = {
  getOneClickVersion: function() {
    try {
      return omaha.oneclickPlugin_.GetOneClickVersion();
    } catch (e) {
      return -1;
    }
  },
  install: function(tag, successCallback, failureCallback) {
    try {
      omaha.oneclickPlugin_.Install("/install " + tag,
        successCallback, failureCallback);
    } catch (e) {
      var errorCode = 0;
      var errorMessage;
      try {
        errorCode = e.number;
        if (!errorCode) {
          errorMessage = e.message ? e.message : e;
          errorCode = parseInt(errorMessage,
            "0x" == errorMessage.substring(0, 2) ? 16 : 10);
        }
      } catch (e2) {}

      if (isNaN(errorCode) || 0 == errorCode)
        errorCode = -2;
      failureCallback(errorCode);
    }
  },
  launchAppCommand: function(guid, isMachine, cmdId) {
    if (9 > omaha.oneclick.getOneClickVersion())
      return false;
    try {
      omaha.oneclickPlugin_.LaunchAppCommand(guid, isMachine, cmdId);
      return true;
    } catch (e) {
      return false;
    }
  },
  getInstalledVersion: function(guid, isMachine) {
    var version = "";
    try {
      version = omaha.oneclickPlugin_.GetInstalledVersion(guid, isMachine);
    } catch (e) {}

    return version;
  }
});

// install application using OneClick

function onSuccess() {
  // ...
}

function onFail(errorCode) {
  // ...
}

if (!omaha.oneclick) {
  // OneClick is not available
} else {
  var tag = "appguid=" + appguid;
  tag += "&appname=" + appname;
  tag += "&needsadmin=" + needsadmin;
  tag += extraParameters;
  omaha.oneclick.install(tag, onSuccess, onFail);
}